Seismic Displacement Hazard and Earth Dam on a Soft Foundation

Olaya F.; Cañabi L. · Geo-Congress 2026: Earthquake Engineering and Soil Dynamics - Selected papers from Geo-Congress 2026 (2026) · DOI: 10.1061/9780784486702.038

Resumen

The evaluation of the seismic performance of earth dams is typically conducted using Newmark-type stick-slip simplified models. In cases where soft materials, that are prone to softening, are present in the dam foundation or body, simplified models are not applicable, and advanced numerical modeling is required. In practice, design ground motions are selected and modified to be consistent with the target design response spectrum. These motions are subsequently used in dynamic analyses to compute seismically induced displacements. In this approach, the design hazard level is chosen for the ground-motion parameter (e.g., PSa) and not for the seismically induced displacements. It is implicitly assumed the hazard level of the ground-motion parameter directly applies to the displacement. However, this assumption has not been proved; on the contrary, different studies have shown that it is not valid. In this paper, the hazard for seismically induced slope displacement of an earth dam is evaluated through displacement hazard curves that directly relate slope displacement to hazard level. A set of hazard-consistent ground motions containing a large number of time histories is used to relate rates of occurrences and subsequently different hazard levels to slope displacement. The finite difference method was used to perform a large number of dynamic analyses, and advanced constitutive models were employed to capture the complex response of the dam materials and its foundation. © ASCE.

Instituciones: Pontificia Universidad Católica del Perú